It is known that the compound 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline (hereinafter for convenience being referred to as "Ethoxyquin") is an antioxidant and that it acts much like vitamin E in many biological functions. It is further known to protect vitamin E-deficient mice and piglets against iron toxicity (Nature, 846 (1964); Acta Agriculture Scandinavica Suppl. 19 (1973)) and in some cases is more efficient than vitamin E itself. Ethoxyquin is also known to act as a growth promoting agent when added to poultry feed (Quarterly Journal Fla. Acad. Sci. 27 (2), 131 (1964)).
However, Ethoxyquin has certain drawbacks in that it is difficult to produce and to store in pure form. The compound is an oil which rapidly and continuously darkens upon storage. Still further, the compound has an unpleasant taste, it is a base, and administration thereof causes problems.
Research has therefore been conducted to find compounds having the properties of Ethoxyquin without having its disadvantages, namely being antioxidant under biological conditions, being able to protect vitamin E deficient animals, for example from iron poisoning, to act as a growth promoting agent and to inhibit amyloidosis. The compounds desired should also not have the undesirable odor or taste of Ethoxyquin, should be able to be produced in pure suitable form for pharmaceutical compounding and to be storable.